1. Field of the Invention
The present invention relates to a data storage medium having still picture data and audio data stored thereon, and an apparatus and method for reproducing the still picture data along with high quality audio data.
2. Description of the Related Art
Conventionally known optical disks which music information including audio data or moving picture information is recorded to and reproduced from include compact disks (CDs) and laser disks (LDs). Compact disk recording and reproduction apparatuses and laser disk recording and reproduction apparatuses are conventionally known apparatuses for recording and reproducing the above-mentioned information.
A CD is an optical disk having a diameter of 12 cm for storing music information digitally recorded using an encoding technology referred to as linear PCM. CDs have been utilized as a medium for storing data for music applications. An LD is an optical disk having a diameter of 30 cm for storing moving picture information with audio data recorded as an analog signal. LDs have been utilized as a medium for storing data for video applications such as movies.
Recently, optical disks having a diameter of about 12 cm for storing music information and moving picture information including audio data digitally recorded. On such optical disks, either one or both of the music information and moving picture information are efficiently recorded in the state of being digitally compressed in order to acquire longer recording times and higher quality. Some of such optical disks have a file structure which facilitates data exchange with computers and communication apparatuses.
In order to meet demands for mediums having higher quality recording and reproduction of audio information than CDs, the DVD-Video technology has been developed and put into practice for realizing high quality audio data reproduction of linear PCM, 96 kHz and 24-bit sampling. However, the DVD-Video standards cannot provide high quality linear PCM multi-surround audio data reproduction or higher quality audio data reproduction. Accordingly, a higher quality technology has been in demand. However, the amount of high quality audio data is quite large and thus the reproduction speed of data required is quite high. Thus, it is difficult to record and reproduce image data along with the high quality audio data.
In the case of reproducing an audio title, there is a demand that the image data be used as supplemental data to the audio data as, for example, a so-called jacket picture such as lyrics and figure of the player. In order to realize this, recording and reproduction apparatuses having more flexible and a wider variety of functions are required. The functions include reproduction of video data synchronously with high quality audio data, reproduction of video data asynchronously from audio data, manipulation of video data by key operation, and special effects at the time of video data switching.
There is another demand that data be reproduced as the title creator intended. For example, the initial operation when the disk is inserted should not be determined by the system used, and direct selection of the audio data should be permitted or prohibited in accordance with the intention of the title creator regardless of the type of the player.
Conventional optical disks, and recording and reproduction apparatuses generally have the above-described structure and thus have a problem in that it is difficult to record and reproduce high quality digital audio data along with video data. When the transfer speed of the high quality audio data is approximately equal to the reading speed of the optical disk, the video data cannot be reproduced along with the audio data by the method of multiplexing the audio data and the video data used in conventional apparatuses. The reason for this is that when the audio data and the video data are multiplexed, the transfer speed of the resultant data exceeds the reading speed of the optical disk and thus the continuous reproduction of such data cannot be guaranteed. The method, often used in computer applications, of appropriately buffering audio data and video data so as to simultaneously reproduce the audio data and the video data which are recorded on different areas of the optical disk cannot be used. The reason for this is that the sum of the transfer speeds of the audio data and the video data needs to be equal to or lower than the reproduction speed of the optical disk in order to continuously reproduce the data recorded on disks such as CDs for an hour or more.
A Browsable reproduction method of switching the video data based on an instruction by the user while continuously reproducing the audio data, or a SlideShow reproduction method of automatically switching the video data in synchronization with a specified position in the audio data are not usable.